Structural Diversity and Properties of Coordination Polymers Built from a Rigid Octadentenate Carboxylic Acid

Abstract

By using a semi-rigid tetracarboxylate ligand 5,5′-(1,4-phenylenebis(methylene))bis(oxy)diisophthalic acid (H4L), three novel coordination polymers were synthesized solvothermally and characterized by single-crystal X-ray diffraction, thermogravimetric, photoluminescent and gas adsorption studies. Compound [Zn(H2L)(H2O)2] (1) is a two-dimensional (2D) network with sql/Shubnikov topology built from the 4-connecting Zn2(OOC)2 cluster and bridging ligand H2L2−. Compound [Co2(H3L)2(H2L)(H2O)2]·5H2O (2) is a one-dimensional (1D) zigzag chain-like polymer made of 2-connecting ligand H2L2− and Co2O6(H2O)4 clusters, which form a 3D network through hydrogen bonding interactions. [Cd3(L)2]·(H3O)2(H2O)(DMF)4 (3) possesses a rare (4,8)-connected flu (CaF2) net built from 8-connecting Cd3 clusters and 4-connecting L ligands. In three complexes, the ligand H4L exhibits diverse coordination configurations and modes owing to its flexibility. Upon excitation at room temperature, complexes 1 and 3 exhibit strong violet and blue emissions, respectively. N2 gas adsorption measurements at 77 K showed that compound 3 possesses permanent porosities.